1994 JEEP WRANGLER check engine

DIAGNOSTIC TROUBLE CODE DESCRIPTIONSÐCONTINUED
Diagnostic
Trouble
CodeDRB Scan Tool
DisplayDescription of Diagnostic Trouble Code
41**..........Generator Field Not
Switching ProperlyAn open or shorted condition detected in the generator field control circuit.
42* ..........Auto Shutdown Relay
Control CircuitAn open or shorted condition detected in the auto shutdown relay circuit.
44* ..........Battery Temp Sensor
Volts out of LimitAn open or shorted condition exists in the engine coolant temperature sensor
circuit or a problem exists in the PCM's battery temperature voltage circuit.
46**..........Charging System Voltage
Too HighBattery voltage sense input above target charging voltage during engine
operation.
47**..........Charging System Voltage
Too LowBattery voltage sense input below target charging during engine operation.
Also, no significant change detected in battery voltage during active test of
generator output.
51**.......... O2SSignal Stays Below
Center (Lean)Oxygen sensor signal input indicates lean air/fuel ratio condition during
engine operation.
52**.......... O2SSignal Stays Above
Center (Rich)Oxygen sensor signal input indicates rich air/fuel ratio condition during
engine operation.
53* ..........Internal PCM Failure PCM Internal fault condition detected.
or
PCM Failure SPI
CommunicationsPCM Internal fault condition detected.
54* .......... NoCamSync Signal at
PCMNo fuel sync (camshaft signal) detected during engine cranking.
55* .......... N/ACompletion of diagnostic trouble code display on the Malfunction Indicator
Lamp (Check Engine Lamp).
62* .......... PCMFailure SPI miles not
storedUnsuccessful attempt to update SPI miles in the PCM EEPROM.
63* .......... PCMFailure EEPROM
Write DeniedUnsuccessful attempt to write to an EEPROM location by the PCM.
* Check Engine Lamp will not illuminate at all times if this Diagnostic Trouble Code was recorded. Cycle Ignition key as
described in manual and observe code flashed by Check Engine lamp.
** Check Engine Lamp will illuminate during engine operation if this Diagnostic Trouble Code was recorded.
JFUEL SYSTEM 14 - 53

INSTALLATION
(1) Install the fuel injector(s) into the fuel rail as-
sembly and install retaining clip(s).
(2) Install fuel rail. Refer to Fuel Rail Installation
in this section.
(3) Start engine and check for fuel leaks.
FUEL PUMP MODULE
Refer to the Fuel Delivery System section of this
group for removal/installation procedures.
FUEL PUMP RELAY
The Fuel Pump relay is located in the Power Dis-
tribution Center (PDC) (Figs. 1 or 2). For location of
this relay within the PDC, refer to label on PDC
cover.
FUEL RAIL ASSEMBLY
REMOVAL
WARNING: THE FUEL SYSTEM IS UNDER CON-
STANT FUEL PRESSURE (EVEN WITH THE ENGINE
OFF) OF APPROXIMATELY 131-269 KPA (19-39
PSI). THIS PRESSURE MUST BE RELEASED BE-
FORE SERVICING THE FUEL RAIL.
(1) Remove fuel tank filler tube cap.
(2) Disconnect the negative battery cable from bat-
tery.
(3) Perform the Fuel System Pressure Release Pro-
cedure as described in the Fuel Delivery System sec-
tion of this Group.
(4) Remove and numerically attach a tag (if fuel
injector is not already tagged), the injector harness
connectors. Do this at each injector (Fig. 7).
(5) Disconnect vacuum line from fuel pressure reg-
ulator (Fig. 7).
(6) Disconnect fuel supply line from fuel rail and
the fuel return line from fuel pressure regulator (Fig.7). Refer to Fuel Tubes/Lines/Hoses and Clamps, or
Quick-Connect Fittings. These can both be found in
the Fuel Delivery section of this group.
(7) Remove fuel rail mounting bolts.
On models with automatic transmissions, it may be
necessary to remove automatic transmission throttle
line pressure cable (and bracket). This will aid in fuel
rail assembly removal.
(8) Remove fuel rail by gently rocking until all the
fuel injectors are out of the intake manifold.
INSTALLATION
(1) Position tips of all fuel injectors into the corre-
sponding injector bore in the intake manifold. Seat
injectors into manifold.
(2) Tighten fuel rail mounting bolts to 27 Nzm (20
ft. lbs.) torque.
(3) Connect injector harness connectors to appro-
priate (tagged) injector.
(4) Connect both fuel lines to fuel rail.
(5) Connect vacuum supply line to fuel pressure
regulator.
(6) Install protective cap to pressure test port fit-
ting.
(7) Install fuel tank cap.
(8) Connect negative battery cable to battery.
(9) Start engine and check for fuel leaks.
FUEL SYSTEM PRESSURE RELEASE PROCEDURE
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH THE ENGINE OFF)
OF APPROXIMATELY 100 KPA (14.5 PSI). BEFORE
SERVICING THE FUEL PUMP, FUEL LINES, FUEL
FILTER OR FUEL INJECTOR, THE FUEL SYSTEM
PRESSURE MUST BE RELEASED.
Refer to the Fuel Delivery System section of this
group. See Fuel Pressure Release procedure.
FUEL TANKS
Refer to the Fuel Tank section of this group for re-
moval/installation procedures.
FUEL TANK PRESSURE RELIEF/ROLLOVER VALVE
Refer to the Fuel Tank section of this group for re-
moval/installation procedures.
FUEL TUBES/LINES/HOSES AND CLAMPS
Refer to the Fuel Delivery System section of this
group for removal/installation procedures. Also refer
to Quick-Connect Fittings in the Fuel Delivery sec-
tion of this group.
IDLE AIR CONTROL (IAC) MOTOR
The IAC motor is mounted to the throttle body ad-
jacent to the throttle position sensor (Fig. 8).
Fig. 7 Fuel Injector HarnessÐTypical
14 - 56 FUEL SYSTEMJ

(3) Lower the vehicle.
PARK NEUTRAL SWITCH
Refer to Group 21, Transmissions for park neutral
switch service.
POWER STEERING PRESSURE SWITCHÐ2.5L
ENGINE ONLY
The power steering pressure switch is installed in
the power steering high pressure hose (Figs. 11 or
12).
REMOVAL
(1) Disconnect the electrical connector from the
power steering pressure switch.
(2) Place a small container or shop towel beneath
the switch to collect any excess fluid.
(3) Remove the switch.
INSTALLATION
(1) Install the power steering switch.
(2) Connect the electrical connector to the switch.(3) Check power steering fluid and add as neces-
sary.
(4) Start the engine and again check power steer-
ing fluid. Add fluid if necessary.
POWERTRAIN CONTROL MODULE (PCM)
On XJ models, the PCM is located in the engine
compartment next to the air cleaner (Fig. 13). On YJ
models, the PCM is located in the engine compart-
ment behind the windshield washer fluid reservoir
(Fig. 14).
REMOVAL
(1) Disconnect the negative battery cable at the
battery.
(2) YJ Models Only: Remove the windshield
washer fluid tank.
(3) Loosen the 60-Way connector mounting bolt
(Figs. 13 or 14).
(4) Remove the electrical connector by pulling
straight back.
(5) Remove the three PCM mounting bolts.
(6) Remove PCM.
Fig. 11 Power Steering Pressure SwitchÐYJ Models
Fig. 12 Power Steering Pressure SwitchÐXJ Models
Fig. 13 PCM LocationÐXJ Models
Fig. 14 PCM LocationÐYJ Models
14 - 58 FUEL SYSTEMJ

the sensor will not rotate, install the sensor with the
throttle shaft on the other side of the socket tangs).
The TPS will be under slight tension when rotated.
(1) Install the TPS and retaining bolts.
(2) Connect TPS electrical connector to TPS.
(3) Manually operate the throttle (by hand) to
check for any TPS binding before starting the en-
gine.
TORQUE CONVERTER CLUTCH RELAY
On YJ models, the TCC relay is located in the en-
gine compartment. It is attached to the cowl panel
with one bolt (Fig. 20). On XJ models, the TCC relay
is located in the power distribution center (PDC)
(Fig. 21). For location of this relay within the PDC,
refer to label on PDC cover.
VEHICLE SPEED SENSOR
The vehicle speed sensor (Fig. 22) is located on the
extension housing of the transmission on 2WD mod-
els. It is located on the transfer case on 4WD models.
REMOVAL
(1) Raise and support vehicle.
(2) Disconnect the electrical connector from the
sensor.
(3) Remove the sensor mounting bolt (Fig. 23).
Fig. 18 TPS LocationÐ4.0L Engine
Fig. 19 Throttle Position SensorÐInstallation
Fig. 20 TCC Relay LocationÐYJ Models
Fig. 21 Power Distribution CenterÐXJ Models
Fig. 22 Vehicle Speed Sensor LocationÐTypical
14 - 60 FUEL SYSTEMJ

Wiring Diagram Name Sheet Number
A/C Compressor Clutch........................45
A/C Compressor Clutch Relay....................45
A/C Heater Blower Motor.......................46
A/C Low Pressure Switch.......................45
A/C Mode Selector Switch.......................46
A/C System.............................45, 46
A/C Thermostat..............................45
Antenna Mast...............................47
Ashtray Illumination Lamp.......................26
Automatic Shut Down Relay......................9
Back-up Lamp Switch.........................16
Battery....................................6
Blower Motor............................44, 46
Blower Resistor...........................44, 46
Blower Switch............................44, 46
Body Ground...............................59
Brake Warning Switch.........................42
Camshaft Position Sensor.......................12
Cargo Lamp................................30
Charging System.............................5
Generator.................................5
Check Engine Indicator Lamp..................39, 40
Chime Module..............................43
Chime Module Connector.......................71
Cigar Lighter...............................58
Circuit Breakers
Windshield Wiper Circuit Breaker...............2,33
Connectors
Chime Module Connector......................71
Dash to Instrument Panel Connector A.............64
Dash to Instrument Panel Connector B.............65
Dash to Instrument Panel Connector C.............66
Data Link Connector.........................10
Instrument Cluster Connector 16 Way...........37, 69
Main Body Connector 1.......................70
Power Mirror Connector......................61
Powertrain Control Module Connector..............73
Steering Column Connector 11 Way...............67
Telltale Connector........................38, 68
Transmission Control Module Connector............72
Transmission Data Link Connector................17
Coolant Temperature Switch......................16
Crankshaft Position Sensor......................12
Dash to Instrument Panel Connector A..............64
Dash to Instrument Panel Connector B..............65
Dash to Instrument Panel Connector C..............66
Data Link Connector..........................10
Distributor Ignition Coil........................10
Dome Lamp................................31
Dome and Courtesy Lamps.................29, 30, 31
Cargo Lamp..............................30
Dome Lamp..............................31